Where can I find a good high-level overview of Enterprise technology concepts and how they intermingle?
Such as, what is a:
The book Enterprise Integration Patterns: Designing, Building, and Deploying Messaging Solutions by Hohpe and Woolf, along with its supporting web site http://www.eaipatterns.com/ are terrific resources.
In the same series, Patterns of Enterprise Application Architecture by Martin Fowler is also very valuable. Martin Fowler's website contains a great amount of material, here is a good starting place: http://www.martinfowler.com/articles/enterprisePatterns.html.
SOA Design Patterns by Thomas Erl, and the companion web site, http://www.soapatterns.org/, is even more encyclopedic. I particularly like this treatment of the enterprise service bus pattern and its constituent patterns.
As with all books on patterns, once you've read through the introductory material, they can be used a reference books, allowing you to selectively read the topics that are of interest, and perhaps going back later for a more thorough, cover-to-cover reading.